SCOLYTIDS (COLEOPTERA) ON SNOWFIELDS ABOVE TIMBERLINE IN OREGON AND WASHINGTON

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Abstract
Scolytids were collected from snowfields above timberline in Oregon and Washington. The most productive location was Collier Glacier on Middle Sister Mountain, Ore., where 334 specimens representing 20 species were collected on 4 August 1968. Collections from seven mountains comprised 476 specimens, 12 genera, and 26 species. Hylastes nigrinus (Mann.) made up 63% of the specimens collected. The collections demonstrated that bark beetles had been dispersed vertically and horizontally thousands of feet from the nearest possible source. Phloeosinus chamberlini Blkm. was found 15 miles from the closest known host tree. Behavioral and meteorological factors involved in the dispersal of scolytids to snowfields are known only circumstantially. Certain species are thought to fly skyward initially. Some individuals presumably are carried aloft by warm updrafts and their fallout occurs when the air becomes too cool for flight.